Tarping system for open top containers

ABSTRACT

A relatively lightweight tarping system for use with trailers or other open top containers includes first and second spaced frame members and an elongated flexible member such as a cable or chain connected to and extending therebetween. A tarpaulin may be mounted thereon so that the frame members, flexible member and tarpaulin are pivotable between a covered position atop the open top container and an uncovered position. A four-bar linkage is preferably used in combination with a rotational drive mechanism to provide various advantages in rotating the tarpaulin assembly between the covered and uncovered positions. A width adjustment mechanism is provided to provide usage with trailers or other open top containers of different widths. An improved seal is provided between the tarpaulin and container.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority from U.S. patent application Ser. No.11/732,375, filed Apr. 3, 2007 and U.S. Provisional Application Ser. No.60/788,843 filed Apr. 3, 2006; the disclosures of which are incorporatedherein by reference.

BACKGROUND OF THE INVENTION

1. Technical Field

The invention relates generally to a tarping system for covering opentop trailers. More particularly, the invention relates to such a systemin which a support assembly and tarpaulin are mounted thereon andmovable between a covered position atop the trailer to an uncoveredposition beside the trailer. Specifically, the invention relates to sucha device in which the support system and tarpaulin are pivoted betweenthe covered and uncovered positions.

2. Background Information

It has been long been necessary to cover trailers in order to keep theircontents from blowing out especially when the trailer is being pulled.Laws and covered during transit for this purpose. Even where laws tothis effect do not exist, it is nonetheless beneficial to cover thetrailers to prevent the various negative results of material coming outof the trailers.

Transfer trailers are typically used to haul refuse from a transferstation to a landfill. They are typically loaded from the top by a wheelloader or the like, covered to keep the contents therein and uncoveredupon arrival at the landfill. The tailgate of the transfer trailer isthen opened and a tipper dumps the trailer to empty its load. Otherdumping mechanisms may be used such as a shuffle floor. Many trailersmay be quite long, for instance 53 feet or even longer. The maximumtrailer widths for highways are typically either 96 inches or 102inches. Federal highways allow for 102 inch wide trailer bodies whereassome local areas may restrict the maximum to 96 inches. Laws andregulations also generally allow for an additional width of 3 inches oneach side of the trailer body to allow for safety equipment such aslighting, tarping systems and so forth. Thus, the overall width of atarping system for a highway trailer is limited to a maximum of 102inches for the 96 inch body and 108 inches for the 102 inch body.

While it is possible to manually cover such trailers, it is timeconsuming, expensive and often unsafe. Manual tarping may take 30minutes or more. Manual tarping also requires the operator to climb ontop of the load to spread the tarp and tie it down, which can bedangerous especially if the load is refuse or the like. In addition,trailers can be 13 feet tall or more, thus subjecting operators to fallhazards.

The various types of truck hauling systems typically fall into 3categories. The first is cable tarp systems, which are represented inpatents such as U.S. Pat. Nos. 2,469,958; 4,067,603; 4,189,178;4,725,090; 5,102,182; 5,253,914; 6,142,554 and 6,250,233. The firstcategory employs a continuous loop of cable along the top of each sidewall of the trailer which is revolvable with a sheave at the front orrear of the trailer and a driven sheave at the opposite end. Bows orother cross members extend across the trailer with the tarpaulinconnected thereto. The bows are rigid rods or the like having an archshape or the like which extend upwardly and over the trailer. Therearmost bow is connected to the cable and the other bows are configuredto slide or slip along the cable so that movement of the cable duringthe revolution of the endless cable loop pulls the rear most bow with itwhereby the tarpaulin in turn pulls the remainder of the bows to coverthe trailer.

Because trailer walls are typically at or near the maximum heightallowed, the use of a bow or arch shaped member may put the trailer overthe maximum height. On the other hand, if the cross members are straightinstead of bowed, the tarpaulin tends to be dragged over the load, thusdestroying the tarpaulin and preventing the use of the tarpaulin systemwith loads that are heaped above the trailer walls. Refuse and othermaterials tend to destroy tarpaulins relatively quickly and replacementof a tarpaulin is labor intensive on this type of system. In addition,especially with longer trailers the movements of the two endless loopcables are likely to get out of timing with one another due to cablestretch, which causes the bows to rack, thus making deployment of thetarpaulin difficult and requiring additional maintenance. This type ofsystem also requires a substantial amount of space to store thetarpaulin in its un-deployed position near the front of the trailer,making complete loading of the trailer more difficult. In addition, ifthe side walls belly out, they may hit the cable and make actuationdifficult or impossible.

The second category of tarping systems is a roll type system as shownU.S. Pat. Nos. 2,976,082; 3,384,413; 3,785,694; 4,302,043; 4,505,512;4,657,062; 4,691,957; 4,834,445; 5,002,328; 5,180,203; 5,549,347;5,762,002; 5,765,901 and 6,142,553. The end of the tarpaulin in the rollsystem is attached to the side wall of the trailer and the other end isattached to a torque tube or torsion member that rolls the tarpaulinover the width of the trailer. The tube is held down by means of straps,chains or the like to stretch the tarpaulin over the top of the trailer.Most of these systems are cranked by hand although some are powered.

One problem with roll systems is that they are not fully automatic. Theoperator must manually tie down the tarp and in most cases manually rollthe tarp onto the trailer, which is time consuming. For longer trailers,the torque tube requires a center support extending across the top ofthe trailer to prevent deformation of the torque tube, which makesrotating the tube very difficult. As previously noted, the trailer wallsare typically near or at the maximum height and if an arch is used toroll the tarp over, it may cause the trailer to be over the maximumheight. If no arch is used, the tarpaulin must sometimes roll across aheaped load which can cause damage to the tarpaulin and may beimpossible without the operator climbing on top of the load to hoist theroll over any pieces which stick up abruptly from the load. Thus, thistype of system is typically time consuming, labor intensive and possiblyhazardous.

The third category of tarping systems is the flip tarp system. Thesetarping systems typically have tarpaulins that flip or rotateapproximately 270 degrees from a generally horizontal deployed orcovered position over the load to a vertical uncovered or stowedposition along the side of the trailer. This type of system allowsloading from either side of the trailer. The flip tarp systems typicallyhave a structure which is hinged on the top of one or both side wallswith a tarpaulin connected thereto. Some of these systems may use acable extending the length of the trailer to offer additional support tothe tarpaulin. Such systems use an opening mechanism mounted on thefront of the trailer to rotate the frame structure about the hinges.Examples are shown in US Patent Application Publications 20060043755 and20050127705, as well as in U.S. Pat. Nos. 6,983,975; 6,402,224 and5,542,734. Each of these examples uses hinges on one side of the trailerand opens the covering to one side. Other flip tarp systems utilize acover which has been split into two longitudinal sections that hinge oneach of the side walls of the trailer, as shown in U.S. Pat. Nos.D290591, 4,767,152, 4,627,658, 4,542,931, 4,210,358, 2,408,132 and1,209,265. Although U.S. Pat. No. 4,627,658 shows an operating mechanismat the rear of the trailer, it is generally unfeasible due to the factthat there is no room on a standard trailer as a result of tailgate,width and height limitations. Thus, the other prior art configurationsuse some sort of frame structure or torsion member running from thefront of the trailer to the rear of the trailer in order to operate rearportion of the tarping system.

One disadvantage of the prior flip tarp systems relates to the priorbelief that a torsional structure running the length of a trailer wasrequired to flip the entire tarp over. Because trailers can be 53 feetlong or more, using a frame or torsional structure to operate the rearand/or central portions of the tarping system requires substantialstructure and the associated weight thereof. For example, one prior artflip tarp system uses a 1½ inch solid shaft for the torsional memberwhich weighs over 300 pounds. Due to weight limits imposed by law, thisresults in reducing the amount of the payload that can be hauled withinthe trailer.

In addition, the top rails of these trailers move, deflect and bellyoutward. Thus, if the longitudinal frame or torsional member is hingedwhere the trailer bellies out, the frame structure must also deflect inthe center, causing undue stress and premature failure of the tarpingsystem. If the frame or torsional member is not hinged at the centersection of the trailer wall and the wall bows out in the center, thewall can keep the frame or torsional member from swinging all the wayaround to lie next to the trailer wall. Either way, this can put theframe or torsional member into a bind, causing the tarping system tocease functioning. Moreover, a loader may run up against the side of thetrailer during loading and damage the frame or torsional member whenusing the stated position against the side of the trailer. Furthermore,because a low height is desirable, the frame or torsional membertypically is barely adequate to take the torsion from the driven memberat the front of the trailer to the rear, and thus it is somewhatflexible. Thus, although the frame or driven member may be held down bythe actuating mechanism at the front of the trailer, only the torsionmember serves to hold the tarping mechanism down at the back.

Prior flip tarping systems typically do not do a very good job ofkeeping the material or load within the body of trailer. As the traileris pulled down the highway causing air to blow relative thereto, the airmay blow material out the rear of the trailer. The light torsion tube orframes as discussed above do not suitably keep the tarping system helddown in the rear of the trailer. The bumping up and down of the tarpingsystem or the upward blowing by wind on the tarp tends to cause crackstherein which create openings through which material can escape. Theseprior systems also typically fail to suitably hold the tarping materialdown along the sides of the trailer body, thus creating gaps throughwhich material may be blown out. These prior art systems do not allowfor holding down the moving side of the tarp over the side of thetrailer by a few inches. If the middle of the trailer bellies out, thetarp will sit on top of the bellied out middle of the wall, leaving asubstantial crack between the cable and wall at the front and the rearof the trailer through which material may be blown out. In addition,tarping systems which require a lateral frame structure at the centerportion of the trailer for supporting the tarpaulin can be an impedimentto sealing. More particularly, when the load is heaped up above the sidewalls of the trailer, the lateral frame structure lies atop the heapedup load so that the tarping system cannot seal around its periphery,thus allowing the material to escape.

Another disadvantage relates to the use of operating mechanisms whichuse a roller and track mechanism or sleeve type bearings to operate thetorsional structure. The torsional structure is usually hinged to thewall of the trailer and if the operating mechanism on the front wall andside wall do not stay perpendicular, premature failure of the bearingswill occur due to misalignment.

An additional need is to be able to rotate the tarping system to eitherone side or the other of the trailer, which is partially addressed byU.S. Pat. No. 6,983,975. However, said patent does not provide a tarpingsystem which is capable of handling multiple widths and lengths oftrailers without the need for different parts or the welding ofcomponents that have been cut to length.

The tarping system of the present invention addresses these and otherproblems in the art.

BRIEF SUMMARY OF THE INVENTION

The present invention provides a covering system comprising first andsecond frame members laterally spaced from one another; an elongatedflexible member connected to and extending laterally between the framemembers; a tarpaulin extending between the first and second framemembers and connected to the flexible member; wherein the frame members,flexible member and tarpaulin are pivotable between a generallyhorizontal covered position adapted to cover an open top container andan uncovered position adapted to allow access to the open top.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a side elevational view of a truck and trailer with which thefirst embodiment of the tarping system of the present invention is used.

FIG. 2 is a diagrammatical view showing the relation between FIGS. 2Aand 2B.

FIG. 2A is a top plan view of a front portion of the tarping system.

FIG. 2B is a top plan view of a rear portion of the tarping system.

FIG. 2C is an enlarged top plan view with portions cut away showing theends of the frame assemblies distal their pivotal mounts and showing theframe assemblies out of square prior to the tightening of the cableextending therebetween.

FIG. 2D is similar to FIG. 2C and shows the cable having been tightenedto move the frame assemblies toward one another and into square.

FIG. 3 is a front elevational view taken on line 3-3 of FIG. 2A showingthe front of the tarping system and upper portion of the trailer.

FIG. 4 is an enlarged front elevational view of the width adjustmentmechanism shown in FIG. 3.

FIG. 5 is an enlarged front elevational view of the actuating mechanismshown in FIG. 4 along with the hydraulic connections.

FIG. 6 is an enlarged side elevational view taken on line 6-6 of FIG.2A.

FIG. 7 is an enlarged side elevational view from the opposite directionof FIG. 6 taken on line 7-7 of FIG. 2A.

FIG. 8 is a schematic view of the hydraulic circuits of the tarpingsystem.

FIG. 9 is a schematic view of the electrical system of the tarpingsystem.

FIG. 10 is a front elevational view similar to FIG. 3 showing an initialstage of movement of the drive arm with the latch in the unlatchedposition.

FIG. 11 is similar to FIG. 10 and shows a further stage of moving thetarping system to uncover the trailer with movement of the rear frameassembly trailing the movement of the front frame assembly.

FIG. 12 is similar to FIG. 11 and shows a further stage of uncoveringthe trailer with the front frame assembly in a substantially verticalposition.

FIG. 13 is similar to FIG. 12 and shows a further stage of movement withthe front frame assembly having moved past vertical and the rear frameassembly having swung forward of the front frame assembly.

FIG. 14 is similar to FIG. 13 and shows a further stage of movement ofthe tarping system as it moves downwardly toward the stowed position.

FIG. 15 is similar to FIG. 14 and shows the tarping system at a furtherstage of movement with the rear frame assembly in a vertical positionbeside the side wall of the trailer and the front frame assemblytrailing the movement of the rear frame assembly.

FIG. 16 is similar to FIG. 15 and shows the tarping system in the stowedposition with both frame assemblies in a vertical position against theside wall of the trailer.

FIG. 17 is similar to FIG. 2A and shows a portion of a pair of catenarycables extending between the front and rear front assemblies.

FIG. 18 is similar to FIG. 1 and shows the tarp and catenary cables atopa load within the trailer which is heaped up above the side wallsthereof.

FIG. 19 is an enlarged front elevational view similar to FIG. 5 showinga second embodiment of the actuating mechanism.

FIG. 20 is similar to FIG. 19 and shows a third embodiment of theactuating mechanism.

FIG. 21 is a top plan view of a front portion of a second embodiment ofthe tarping system of the present invention showing two tarp assemblieseach covering a portion of the trailer.

FIG. 22 is a front elevational view taken on line 22-22 of FIG. 21showing the tarp assemblies in the covered position.

FIG. 23 is similar to FIG. 22 and shows the tarp assemblies in a processof opening.

Similar numbers refer to similar parts throughout the drawings.

DETAILED DESCRIPTION OF THE INVENTION

A first embodiment of the tarping system of the present invention isindicated generally at 10 in FIG. 1, and a second embodiment isindicated generally at 200 in FIGS. 21-23. System 10 is shown atop anopen top trailer 12 which is towed by a truck 14. Tarping system 10 maybe used equally well with railroad cars or any other open top container.Trailer 12 includes a bottom wall or floor 16 and front and rear walls18 and 20 extending upwardly therefrom and defining therebetween alongitudinal direction and length of trailer 12 each of which isrepresented at L in FIG. 1. Trailer 12 further comprises first andsecond side walls 22 and 24 extending upwardly from floor 16 anddefining therebetween an axial direction of trailer 12. Rear wall 20 istypically in the form of a tailgate which is pivotally mounted to one ofthe sidewalls 22 and 24 and latched to the other of the sidewalls 22 and24. Alternatively, the tailgate may be pivotally mounted adjacent itstop in order to flip open during the dumping of material from withintrailer 12. The longitudinal and axial directions of trailer 12 willlikewise be applied to tarping system 10 to simplify the description.Trailer 12 has a top 17 (FIGS. 3-4) and defines an interior chamber 25(FIG. 2A) which is bounded by front wall 18, rear wall 20, side walls 22and 24 and floor 16, and which extends from floor 16 to top 17.

System 10 includes front and rear substantially rigid frame assemblies26 and 28 which are pivotally mounted on first side wall 22. A flipperassembly 32 is mounted on front wall 18 of trailer 12 for flipping thesupport assembly and the tarpaulin 30 between covered and uncoveredpositions. A tarpaulin 30 may be mounted on first and second assemblies26 and 28, which serve as supports or part of the support assembly fortarpaulin 30. Alternatively, tarpaulin 30 may not be mounted to thefirst and second assemblies 26 and 28, as detailed further below.Tarpaulin 30 is sized to completely cover the top of trailer 12 and mayhang over the top edges thereof in some areas. Tarpaulin 30 may beformed of any material suitable for covering such an open top container.The tarpaulin 30 may be any suitable sheet material, including but notlimited to, materials such as canvas, woven materials, mesh materials,expanded metal, plastic sheeting or meshes, plastic coated wovenmaterials. As will be appreciated, mesh material may be preferable forsome situations especially in that it limits the effects of winds bothwhen opening the tarp and also during travel. Solid materials may bepreferable for better excluding water from the load being covered.

Referring to FIG. 2A, first frame assembly 26 is a generally triangularstructure which includes a straight first beam 34A and a second beam 36Ahaving a straight central section and end portions which are joined tothe central section by segments which are curved in opposite directionsso that the end portions are substantially parallel. Assembly 26 furtherincludes a base 38A in the form of an angle which is mounted at the topof first side wall 22 adjacent to and overhanging front wall 18 oftrailer 12. Beams 34A and 36A are pivotally mounted on base 38A aboutlongitudinally extending axis which is generally parallel to side wall22. Base 38A is preferably removably mounted on side wall 22 such as byplurality of bolts or the like so that assembly 26 may be removed foruse with another trailer or so that it may be positioned on the otherside wall 24 if desired. A first set of spaced ears 40A is mounted onbase 38A and extends outwardly therefrom adjacent front wall 18 and asecond set of spaced ears 42A extends outwardly from base 38A adjacentits rear end. Respective bolts 44 extend through hole formed in ears 40Aand 42A and serve as pivots on which first and second beams 34A and 36Aare pivotally mounted adjacent respective first ends 46A and 48Athereof. Beams 34A and 36A typically include cylindrical tubes at theirrespective first ends 46A and 48A in which are preferably disposedbearings 50 and through which bolts 44 extend whereby bearings 50facilitate rotational movement of assembly 26. Grease ports aretypically provided for lubricating bearings 50. Beams 34A and 36A haverespective second ends 52A and 54A adjacent which a short third beam 56Ais mounted between beams 34 and 36 via bolts 58, nuts 57 and fenderwashers 60 which are used to spread the force applied by bolt 58 to thepreferably hollow beams 34A, 36A and 56A. A plurality of axially spacedholes 59 (FIG. 3) are formed through third beam 56A for receivingtherethrough bolts 58 and allowing for axial adjustment of beam 56A toselectively provide different axial widths of assembly 26 as shown inFIG. 4, thus providing a width adjustment mechanism to accommodatetrailers of different widths. An end member 61A is connected to andextends downwardly from the outer end of beam 56A.

Referring to FIG. 2B, second frame assembly 28 has a generallytriangular configuration and is substantially a mirror image of firstframe assembly 26. Thus, assembly 28 includes the same members asassembly 26 as described thus far so that second assembly 28 will not bedescribed in further detail except to indicate that various of thenumbered elements of assembly 26 which end in letter A are representedby analogous elements ending in the letter B in assembly 28, such asfirst beam 34A in assembly 26 and the first beam 34B in assembly 28.Tarpaulin 30 may be connected to assemblies 26 and 28 by plurality offasteners 62 which may take various forms, such as snaps, screws, bolts,zip ties and so forth. Although assembly 28 is substantially a mirrorimage of assembly 26, one exception is the connection of a tie downmember 64 which is typically in the form of a strap, rope or otherflexible elongated member suitable for manually tying down assembly 28to trailer 12 via a tied down mount 66 (FIG. 1) mounted on rear wall 20of trailer 12. Tie down member 64 is connected to first beam 34Badjacent second end 52B thereof via a bolt 68 and associated washer orother suitable mechanisms. Other suitable latching mechanisms may alsobe used, such as a spring actuated hook similar to latch assembly 94.This latching mechanism may be opened manually by a rope, cable or thelike.

Overcoming one of the problems of certain prior art tarping systems,first and second assemblies 26 and 28 are preferably not coupled to oneanother by a torsional member. However, assemblies 26 and 28 areconnected to one another by an linearly elongated member which isgenerally and torsionally flexible shown in the form of a cable 70 whichis typically under tension when the tarpaulin support assembly isassembled. However, depending on the specific size and configuration ofthe tarping system, cable 70 may not be under initial tension in thecovered position. A chain, a synthetic line or other suitable flexiblemember may be used instead of cable 70. A turnbuckle 72 (FIG. 2A) isprovided for adjusting the tension of cable 70. Cable 70 adjacent itsfront end is connected to an eye bolt 74 of turnbuckle 72 via a thimble76 looped through the eye bolt and a pair of cable clamps 78 forclamping a folded portion of cable 70 to itself. A second threaded bolt80 of turnbuckle 72 extends through a hole formed in end member 61A toconnect turnbuckle 72 thereto. Adjacent its rear end, cable 70 isconnected to end member 61B in any suitable fashion, such as an eye boltwith a thimble and cable clamps as previously noted. Thus, end members61A and 61B serve as cable mounting members and more particularlyprovide for the mounting of cable 70 below the lower surface of thehorizontal structures of frame assemblies 26 and 28. Thus, cable 70extends laterally in the longitudinal direction external to trailer 12adjacent second side wall 24 and preferably below top 17 of thecontainer. This position of cable 70 allows the length of tarp 30 alongside wall 24 to extend downwardly below top 17 and more particularly tobe stretched over the intersection of top 17 and side wall 24 to providea better seal with top 17 to help reduce spaces through which materialfrom the load inside trailer 12 can be blown out.

Referring to FIGS. 2A and 2B, another flexible member in the form of acable 82 is connected to ears 40B at the rear of trailer 12 and extendsforward to and is connected to an eye bolt of another turnbuckle 84 aspreviously described with regard to turnbuckle 72 and cable 70. Moreparticularly, cable 82 extends through holes formed in ears 42A and 42Band may also pass through other support structures extending from sidewall 22 so that cable 82 is preferably positioned below top 17 oftrailer 12. Turnbuckle 84 is mounted on ears 40A adjacent front wall 18of trailer 12. Tarp 30 is connected to cables 70 and 82 with a pluralityof zip ties 86 which are longitudinally spaced from one another. Asshown in FIGS. 6 and 7, zip ties 86 loop around cables 70 and 82 andalso around turnbuckles 72 (FIG. 7). Zip ties 86 further loop throughrespective holes 88 formed in tarpaulin 30 along the respective edgesthereof adjacent cables 70 and 82. Grommets are typically used toreinforce holes 88. The positioning of cable 82 below top 17 of trailer12 allows top 30 to fold down over the top of side wall 22 similar tothe opposite side to provide a better seal. Alternately, tarp 30 may beconnected to first side wall 22 by various types of connectors insteadof being mounted on a cable such as cable 82. Moreover, tarpaulin 30 maybe mounted only on cable 70 and cable 82, or only on cable 70 and sidewall 22 instead of cable 82. That is, tarpaulin 30 may not be connectedto frame assemblies 26 and 28, as previously noted.

Referring to FIGS. 2C and 2D, some steps of assembling the supportassembly of floor tarpaulin 30 are described. Once each base 38 ofassembly 26 and 28 is mounted on trailer 12 to fix the position of base38A and base 38B with respect to one another, cable 70 may be tightenedwith the use of turnbuckle 72 to apply the appropriate amount of tensionthereto. FIG. 2C shows the outer ends of assemblies 26 and 28 prior tothe tightening of cable 70 and FIG. 2D shows cable 70 in the tightenedposition. Depending on the size of tarp 30 and other factors, thetension of cable 70 will vary. Typically, cable 70 is under a tension ofsomewhere in the range 300 pounds, and more broadly between 100 poundsand 1000 pounds. As FIG. 2C shows, the straight beams 34 and 56 of eachassembly 26 and 28 are out of square with one another prior to thetightening of cable 70. As turnbuckle 72 is rotated (Arrow A) to tightencable 70 to the final position shown in FIG. 2D, the outer ends ofassemblies 26 and 28 are deflected toward one another as indicated asarrows C in order to bring beams 34 and 56 of assemblies 26 and 28 intosquare or to make them substantially parallel to one another and tofront and rear walls 18 and 20 of trailer 12. To simplify the task ofsetting the tension on cable 70, a tension indicator is provided by theuse of a spring washer 90 and a flat washer 92 mounted on bolt 80 sothat spring washer 90 is disposed between flat washer 92 and end member61A. In FIG. 2C, spring washer 90 is shown at rest in an expandedposition in which it has not yet been compressed. FIG. 2D shows that asturnbuckle 72 is tightened, spring washer 90 moves (Arrow B) to acompressed or flat state or position. The movement of spring washer 90to this flat or compressed state during the tightening of cable 70 viaturnbuckle 72 indicates that cable 70 has reached the approximate degreeof tension desired. Alternatively, a compression spring may be used inplace of spring washer 90.

With reference to FIGS. 2A, 3 and 4, a securing mechanism in the form ofa latch assembly 94 for securing frame assembly 26 to front wall 18 oftrailer 12 is described. Assembly 94 includes a mounting plate 96mounted on the front side of beam 34A, a latch 98 pivotally mounted onmounting plate 96 and a spring 100 which biases latch 98 toward asecured position in engagement with a catch 102 mounted on front wall 18of trailer 12. Spring 100 extends between and is connected to each ofmounting plate 96 and latch 98. A release cable 104 or other elongatedmember is connected adjacent one end thereof to latch 98 and forms partof a release mechanism for automatically releasing latch 98 to allowtarp 30 and its support assembly to move out of the covered position.

With reference to FIGS. 2A, 3 and 5, flipper assembly 32 is described ingreater detail. Assembly 32 includes a rotary actuator 106 which ishydraulically powered by a hydraulic power pack 108 and on which ismounted a drive arm 110 which is rotatably driven by actuator 106 abouta longitudinally extending axis which is substantially parallel to andoffset from the axis about which assemblies 26 and 28 pivot. Drive arm112 is spaced forward of power pack 108 at about the same height andthus protects power pack 108 from branches and the like during travel.Actuator 106 is secured to a mounting member in the form of a mountingplate 112 which is secured to front wall 18 of trailer 12. Arm 110 issecured to the drive shaft of actuator 106 via a plurality of bolts 114arranged in a circular pattern. Although not shown, an inner and anouter ring are disposed within the hollow interior of arm 110respectively inside of and outside of the circular pattern of bolts 114to serve as spacers which provide strength to the connection between thearm 110 and actuator 106 and assist in translating torque therebetween.Feed and return hydraulic lines 116 are suitably connected betweenactuator 106, power pack 108 and a hydraulic tank 118.

A first portion of arm 110 extends substantially parallel to front wall18 and a second portion angles inwardly toward wall 18 to a free endthereof on which is mounted a cap plate 120. A link 122 is mounted atone of its ends to cap plate 120 and at its opposite end to a boss 124mounted on beam 34A. Boss 124 extends into the interior chamber ofhollow beam 34A and abuts the inner surface of the rear wall thereof toreinforce the connection when bolted onto beam 34A. Preferably, each endof link 122 is connected respectively to plate 120 and boss 124 by balland socket connections 126 or other pivotal connections which allow forpivotal movement in multiple directions. In the exemplary embodiment,link 122 includes a pair of substantially spherical members at each endto provide this pivotal connection. However, other suitable pivotalconnections may be used. Preferably, each pivotal connection 126provides at least two degrees of freedom. Release cable 104 at one endthereof is connected to link 122 at a location adjacent its connectionto boss 124 but spaced radially outwardly therefrom a suitable distancefor pulling cable 104 to provide the release mechanism as describedfurther below.

In the exemplary embodiment, link 122 is an extendable retractableassembly and in particular is shown as a piston cylinder combinationproviding linear extension and retraction. Depending on the specificembodiment, link 122 need not be extendable and retractable. Thisextendable aspect of link 122 allows drive arm 110 to pivot from itsposition shown at FIG. 3, in which it is over center with respect topivotal connection 126 at boss 124 there below, to subsequent positionsin which it is over center in the opposite direction with respect topivotal connection 126 at boss 124. Thus, drive arm 110 may be disposedbelow the upper surface of frame assembly 26 in the covered position sothat arm 110 does not add to the height of the trailer. When heightlimitations are not at issue, drive arm 110 may be disposed upwardly ofassembly 26 in the covered position and thus not need a link such aslink 122 which provides extension and retraction. In another embodiment,the pivots may be configured such that link 122 drives frame assembly 26upward from below. When the frame assembly rotates to its fully openposition along the first side wall 22, the extension capability of link122 allows the drive arm 110 to pass the frame assembly 26 and storeinward of such frame assembly 26 such that the overall width of thetrailer 12 is minimized.

Power pack 108 is mounted on mounting plate 112 by another mountingplate 113 secured thereto and a support arm 115 which extends outwardlyin the forward direction from mounting plate 113. Another support arm inthe form a channel 117 is connected to and extends forward from mountingplate 112 adjacent first side wall 22. Channel 117 includes an anglewhich is matingly connected to the overhanging portion of base 38A by apair of bolts to provide additional strength between plate 112 and base38A.

Flipper assembly 32 thus provides a 4-bar linkage in which the four armsare drive arm 110, link 122, beam 34A of assembly 26 and the body oftrailer 12 when mounted thereon. Alternately, the fourth arm may be madeup of mounting plate 112, channel 117 and base 38A via the connectionbetween. The use of this 4-bar linkage with rotary actuator 106 oranother rotational drive eliminates the need for rollers mounted on alink which rollably engage another link typically within a track. Thisalso eliminates the need for a slidable/pivotal connection, such as aprojection on a link which pivots and slides within a slot, track,passage or the like. In addition, the use of pivotal connections 126 onlink 122 provides an advantage in that any stress which may have beeninduced into flipper assembly 32 as a result of deflection between frontwall 18 and side wall 22 is eliminated because pivotal connections 126do not allow transfer of any forces other than the axial force alonglink 122.

Referring to FIG. 8, the hydraulic controls are described. Power pack 55includes a tank such as tank 118 which may be part of the hydraulicsystem of truck 14 or may be separate. Power pack 55 further includes asuction strainer 128, an electric motor 130 that drives a hydraulic pump132, a relief valve 134, a pressure filter 136 and a solenoid 138operated directional control valve 140. A pair of hydraulic lines 116which are indicated at 116A and 116B in FIG. 8 are connected to controlvalve 140. A pair of flow control valves 142 and 144 communicate withlines 116A and 116B along the hydraulic path to rotary actuator 106.Alternately, on trucks 14 that have hydraulic power, a splitter valveand separate control valve may be used instead of the hydraulic powerpack 55.

Referring to FIG. 9, the electrical controls are detailed. Electricalpower is provided by a battery 146 of tractor 14 or the like. A circuitbreaker 148 is connected to a positive terminal of battery 146. Wiresrun from both the positive and negative terminals to a connector 150which allows tractor 14 to be disconnected from trailer 12. Fromconnector 150, the negative side is connected to motor 130, valvesolenoid 138 and the negative terminal of motor solenoid 152. Thepositive side is connected to a switch box 154 and a first terminal 156of motor solenoid 152. A second terminal 158 of motor solenoid 152 isconnected to motor 130. Switch box 154 is also connected to the positiveterminal of motor solenoid 152 and valve solenoid 138. Switch box 154includes an open button 160 or switch and a closed button 162 or switchassociated with opening and closing the tarping system.

The opening of tarpaulin 30 and its support system from the coveredposition shown in FIG. 10 to the stowed position shown in FIG. 16 ishydraulically powered. Thus, the operation of the hydraulic systemduring opening is now described. Open button 160 of switch box 154 isactuated to energize electric motor 130 and solenoid 138. Motor 130drives hydraulic pump 132 to draw hydraulic fluid from tank 118 throughsuction strainer 128 into pump 132 which pressurizes the fluid. Reliefvalve 134 limits the maximum hydraulic pressure typically to about 3000psi. Fluid is pumped through pressure filter 136 and the flow thereof isdiverted to line 116A because directional control valve 140 isactivated. Fluid flows from line 116A to pressure compensated flowcontrol valve 142 directly through a check valve thereof. Hydraulicfluid subsequently flows to actuator 106, causing it to rotate in anopening direction to move tarpaulin 30 from the uncovered positiontoward the stowed position, as discussed in greater detail below. Fluidfrom actuator 106 flows through pressure compensated flow control valve144 which limits the flow to a setting thereof. Fluid continues throughline 116B through directional control valve 140 and back to tank 118.Control valves 142 and 144 may be included as part of power pack 108 ormay be replaced with other types of valves such as counter balancevalves which would, like valves 142 and 144, control motion of thetarping system in an over center condition, and additionally would lockthe tarping system in any position unless pressure and flow wereprovided to one side or other of rotary actuator 106. This is aparticular advantage in locking the assembly 26 down to the top 17 ofthe trailer 12 during transport. Such counterbalance valve may bemounted directly to the rotary actuator 106.

To close or move the tarp system from the stowed position to the coveredposition, close button 162 of switch box 154 is actuated. Once again,motor 73 is energized so the hydraulic fluid is drawn from tank 118through suction strainer 128 into pump 132 and through pressure filter136 via relief valve 134. However, flow is diverted into line 116Bbecause directional control valve 140 is deactivated. The flow ofhydraulic fluid is thus reversed through control valve 144 to rotateactuator 106 in an opposite direction for closing the tarpaulin. Fluidcontinues from actuator 106 through control valve 144 which limits theflow, and then back through line 116A, through valve 140 and into tank118. If it is desired to mount the tarping system to rotate from secondside wall 24 of trailer 12, hydraulic lines 116A and 116B may beswitched at directional control valve 140. This will allow for theopposite flow of hydraulic fluid through actuator 106 while theelectrical connections remain the same so that open switch 160 willstill open the tarp and close switch 162 will close the tarp.

Referring to FIG. 9, the operation of the electrical system is brieflydescribed. When open button 160 is pushed or otherwise actuated, valvesolenoid 138 and the positive terminal of motor solenoid 152 areenergized. Energizing the positive terminal of motor solenoid 152connects the positive of battery 146 from first terminal 156 to secondterminal 158 to energize motor 130 for raising tarpaulin 30 from the topof trailer 12 away from the uncovered position and toward the stowedposition. When the close switch 162 is energized only the positiveterminal of motor solenoid 152 is energized; valve solenoid 138 is notenergized. Energizing the positive terminal of motor solenoid 152 againconnects the positive of battery 146 from first terminal 156 and secondterminal 158 to energize motor 130 and thus close tarpaulin over 30trailer 12.

The operation of tarping system 10 is furthered described with referenceto FIGS. 10-16. The tie down member 64 is first released. When openswitch 160 is activated, rotary actuator 106 rotates its drive shaft torotate drive arm 110 therewith as indicated at arrow D in FIG. 10. Link122 moves in response to the pivotal movement of drive arm 110, pivotingat its pivotal connections 126 with plate 120 and boss 124. The movementof link 122 causes the movement of release cable 104 to pivotally movelatch 98 (Arrow E1) so that it overcomes the spring bias force of spring100 and releases from catch 102. At this stage, tarpaulin 30 and itssupport assembly remain in the covered position, in which the members ofassemblies 26 and 28 are substantially coplanar within a horizontalplane.

FIG. 11 shows drive arm 110 rotated to a further degree in order tobegin pivotally raising first frame assembly 26 (Arrow E2) via link 122.Initially, first frame assembly 26 is pivotally raised while secondframe assembly 28 remains in abutment with the top of trailer 12.However, as frame assembly 26 continues its upward movement as shown inFIG. 11, it pulls second frame assembly 28 upwardly (Arrow F) via theconnection of cable 70. Thus, the raising of second assembly 28 lagsbehind the raising of first frame assembly 26 and in the exemplaryembodiment is driven only by the connection of the two frame assembliesby cable 70, the tension of which increases and thus also pulls secondframe assembly 28 toward first frame assembly 26 to some degree duringthis movement. As shown in FIG. 11, the first and second frameassemblies 26 and 28 are circumferentially spaced from one another by anangle X which during the raising motion of tarpaulin 30 and the supportassembly is at its greatest when second assembly 28 is on or closelyadjacent top 17 of trailer 12. During this raising motion, angle Xrepresents a rotational lag of second assembly 28 behind first assembly26 which is due in part to the fact that first and second assemblies 26and 28 are pivotable relative to one another. This rotational lagcreates a substantially vertical component of the tension in cable 70which must be great enough in order to provide a lifting force fromfirst assembly 26 to second assembly 28 to pivotally move secondassembly 28. Angle X also represents that assemblies 26 and 28 move outof the coplanar relationship of the covered position and remains in anon-coplanar configuration through most of the rotational movementbetween the covered and stowed positions.

In the exemplary embodiment, cable 70 transmits all of the force fromfirst frame assembly 26 to second assembly 28 which is needed to movesecond assembly out of the horizontal covered position. Thus, theexemplary embodiment eliminates the need for torque tubes or any torsionbars or members for translating torque from assembly 26 to 28. Theelimination of such torque tubes or other torsion members reduces theweight substantially especially where the container to be covered isfairly long. However, it is contemplated that other substantially rigidstructural frame members may extend between and be connected to each ofassemblies 26 and 28 without departing from the spirit of the invention.In any case, cable 70 will be needed in order to transfer sufficientforce from assembly 26 to assembly 28 in order to move assembly 28 outof the covered position. However, the use of other members extendingbetween the assemblies 26 and 28 may provide for some torquetransmission, preferably without adding much weight to the tarpassembly. Cable 70 will provide a force transmitted from first assembly26 to second assembly 28 to provide any amount of the torque about bolts44 required to pivot assembly 28 out of the covered position. Mosttypically, cable 70 will provide such a transmitted force to provide atleast fifty percent of the torque about bolts 44 required to pivotassembly 28 out of the covered position, although this number may be anypercentage between fifty and one hundred percent in most instances. Mosttypically, cable 70 will limit angle X between assemblies 26 and 28during lifting to 50 degrees or less. Depending on various factors suchas the amount of initial tension on cable 70, the length and width ofthe tarp assembly, and the weight of second frame assembly 28, cable 70may limit angle X to no more than 40 degrees, 30 degrees, 20 degrees orless.

FIG. 12 shows arm 110 having rotated to a further degree as indicated atarrow G so that beam 34A, beam 36A (not shown in FIG. 12) and beam 56Aare in a vertical position while second frame assembly 28 has moved asindicated arrow H to a position in which the analogous members thereofare off vertical and still lag behind those of first frame assembly 26.Angle X at this stage is somewhat less than that in the earlier stagesdue to the fact that the amount of weight which must be supported bycable 70 at this point is reduced relative to the earlier stages.

FIG. 13 shows drive arm 110 having rotated to a further degree asindicated at arrow J so that first frame assembly 26 has moved past thevertical indicated by line Z to a degree which has allowed second frameassembly 28 to free fall as indicated at arrow K to a position ahead offirst frame assembly 26. This free fall movement of assembly 28 ishalted by its connection to first frame assembly 26 via cable 70. AngleX is similar to that of FIG. 12 although it will be slightly increasedat this point. Hydraulic valving ensures that even when the tarpassembly goes over center, it does not cavitate the rotary actuatorwhich would allow first frame assembly 26 to descend uncontrolled. Thus,other than the limited free fall motion of second assembly 28, and thelimited free fall of first assembly 26 when link 122 moves from itsextended position to its contracted position or vice versa, the flippingof tarp 30 and assemblies 26 and 28 is controlled throughout itsmovement.

FIG. 14 shows a further stage of rotation of arm 110 as supportassemblies 26 and 28 and tarp 30 are further lowered and angle X becomessomewhat larger due to the amount of weight of assembly 28 which must besupported by cable 70. FIG. 15 shows second frame assembly 28 havingreached a vertical location closely adjacent or in abutment with firstwall 22 of trailer 12 while first frame assembly 26 remains angledoutwardly as it lags behind with angle X being somewhat less than thatshown in FIG. 14. FIG. 16 shows that both frame assemblies 26 and 28 andtarpaulin 30 has moved to the stowed position in a substantiallyvertical orientation beside first wall 22 of trailer 12. Trailer 12 atthis position is suitable for tipping to unload and being loaded fromfirst side 22 without further damage to tarping system 10 by loaderswhich may damage certain other prior art tarping systems as previouslydiscussed.

To move tarp 30 and the associated assemblies from the stowed positionto the covered position, close button 162 of switch box 154 is actuatedas previously discussed. This would result in the rotational movement ofassemblies 26 and 28 and tarp 30 in the opposite direction asillustrated in reverse order from FIG. 16 to FIG. 10 and subsequently toFIG. 3 in order to automatically reconnect latch assembly 94. Duringthis reverse rotation, drive arm 110 would thus rotate to move firstassembly 26 with second assembly 28 lagging behind and pulled in asimilar manner via cable 70. Assembly 28 would once again undergo alimited pivotal free fall once first assembly 26 moved beyond thevertical position above first side wall 22 so the second assembly alsomoved past this vertical position. Second assembly 28 would thuscontinue downwardly to sit atop container 12 followed by first assembly26.

Referring to FIG. 17, the tarping system may be modified to include oneor more catenary cables or other flexible elongated members which areconnected to and extend between first and second assemblies 26 and 28.Cables 164 are shown connected to beam 36A of assembly 26 via eyebolts.Cables 164 are not under tension other than that created by their ownweight when in a rested state and are allowed to sag or have slacktherein. Thus, as shown FIG. 18, a load within the trailer 12 may beheaped up above the top of the trailer walls so that tarp 30 and thecables 164 may bow upwardly to provide additional room for the loadwhere any applicable maximum height is not exceeded. Cables 164 thusallow for this configuration while giving additional support to tarp 30.It is noted here that the tarping system may be altered to accommodatedifferent length trailers simply by changing the length of the variouscables extending between the first and second frame assemblies. Whenshortening the length, extra cable may be cut off or doubled up. Inaddition, the cables may simply be replaced by different length cablesor the like without substantial cost.

FIGS. 19 and 20 show alternate embodiments for driving the flipperassembly. FIG. 19 shows drive arm 166 which is similar to drive arm 110.A cylindrical drum 168 is connected to arm 166 adjacent its inner endand extends outwardly therefrom. A cable 170 is wrapped around drum 166one and a half times or other suitable amount and is connected adjacentits respective ends to pistons of hydraulic cylinders 172 and 174, whichare connected to front wall 18 of trailer 12. Cylinders 172 and 174 maybe operated to extend and retract the pistons thereof in an oppositemanner (Arrow L) to pull cable 170 to rotate drum 166 and arm 164 (ArrowM) to provide for a covering and uncovering movement of the tarpassembly as previously discussed. Two separate cables attached to thedrum 168 may also be used.

FIG. 20 shows a rack and pinion drive mechanism including a pinion 176which is mounted on arm 164 and a rack 178 which engages and drivespinion 176 to provide rotational movement as indicated at arrow N.Hydraulic cylinder 180 is mounted on front wall 18 for driving rack 178which is configured as a piston or is connected to a piston of hydrauliccylinder 180 to move as indicated at arrow P. The rotational movement ofarm 164 provides the covering and uncovering of the tarping system aspreviously discussed.

Tarping system 200 is now described referring to FIGS. 21-23. Referringto FIG. 21, system 200 includes first and second tarp assemblies 202 and204 which are virtually mirror images of one another and respectivelypivotally mounted on first and second side walls 22 and 24. Becauseassemblies 202 and 204 are basically mirror images, only assembly 202will be described in detail except for the interrelation therebetween.Assembly 202 includes front and rear frame assemblies which aresubstantially mirror images of one another as in the earlier embodiment.However, only front frame assembly 206 is shown in FIG. 21. Assembly 206includes a first straight beam 208 and second beam 210 which is curvedin a similar fashion as beam 36A except that its central section isangled with respect to second beam 210 to a greater degree. Straightbeam 208 may have multiple laterally spaced holes to mount turnbuckle220 and be cut off to accommodate different widths of trailers. Unlikeframe assembly 36A, assembly 206 does not include a third beamsandwiched between the ends of first and second beams 208 and 210.Instead, first and second beams 208 and 210 are connected directly toone another by bolt 212, nut 214 and a pair of fender washers 216. Acable assembly 217 comprising a cable 218 and turnbuckle 220 configuredin the same fashion as previously described extends between the frontand rear frame assemblies. However, turnbuckle 220 is connected to firstbeam 208 adjacent a free end 222 thereof distal its pivoting end. Cable218 is likewise connected to the analogous of first beam of the rearassembly. Unlike frame assembly 26 of tarping system 10, frame assembly206 does not include a downward extension for mounting the cableassembly thereon. Thus, cable assembly 217 is mounted above top 17 oftrailer 12 and extends from front wall 18 to the rear wall (not shown inFIG. 21) of trailer 12 over interior chamber 25. Depending on the lengthof cable 218 and the amount of tension that it may be under, it may ormay not droop below top 17 into interior chamber 25 between the frontand rear walls of trailer 12. First and second beams 208 and 210 arepivotally mounted in the same manner as assembly 26 of tarping system 10and thus include base 38A, ears 40A and 42A and so forth. Cable 82 andturnbuckle 84 are mounted in the same fashion as described in tarpingsystem 10. A tarpaulin 224 may be mounted on the frame assemblies andcable assemblies in the same manner as previously described by fasteners62 and zip ties 86 or in the alternate ways previously discussed.Tarpaulin 224 extends from first wall 22 of trailer 12 to beyond themidpoint between side walls 22 and 24. Thus, the cable assemblies 217 ofeach up top assemblies 202 and 204 run parallel and adjacent to oneanother near the midway point between wall 22 and 24 while thetarpaulins 224 overlap in the center. The free ends 222 of therespective beams 208 are disposed closely adjacent and facing oneanother adjacent this midpoint with beams 208 aligned with one another.

The drive mechanism for rotating tarp assembly 202 out of the coveredposition is very similar to that previously described. The drivemechanism includes rotary actuator 106, link 122 and boss 124 which ispreviously discussed. A drive arm 226 which is a solid member instead ofthe hollow drive arm 110 of system 10 as used. Drive arm 226 is mountedin a substantially similar manner to the rotational drive shaft ofactuator 106 and to link 122 in the same manner as previously discussed.Power pack 108 is used but is mounted centrally on front wall 18 andconfigured for use with both of the drive mechanisms of tarp assemblies202 and 204. To that effect, hydraulic lines 116 are configured toprovide power to each of actuators 106.

In operation, the drive mechanism works in substantially the same manneras previously described except that latch assembly 94 is not used. Ahook 223 is attached to the link 122. In the covered position, hook 223rotates under a pin 225 that is stationary with the front wall 18 tolock the beams 208 to the front wall. This same latching mechanism maybe used on other embodiments. Thus, an electronic control as previouslydescribed is used to operate power pack 108 to provide hydraulic powerto each of rotary actuators 106 to move each of tarp assemblies 202 and204 between their respective covered positions shown in FIGS. 21 and 22to an open position shown in FIG. 23 and ultimately to a stowed positionbeside respective side walls 22 and 24. While the stowed position is notshown, it is substantially the same as the stowed position with system10 except for the assemblies 202 and 204 come down about half thedistance. One advantage to the use of the two tarp assemblies 202 and204 is the lesser torque requirement for opening each of them comparedto that of the tarping assembly of system 10 which extends all the wayacross the trailer. Another advantage is that less room is required tothe side of the trailer during the deployment of the tarping system 200.Another advantage is that there is less area for wind to act upon,causing less stress, during deployment of tarping system 200.

Thus, tarping systems 10 and 200 provide for several advantages over theprior art systems as previously discussed.

In the foregoing description, certain terms have been used for brevity,clearness, and understanding. No unnecessary limitations are to beimplied therefrom beyond the requirement of the prior art because suchterms are used for descriptive purposes and are intended to be broadlyconstrued.

Moreover, the description and illustration of the invention is anexample and the invention is not limited to the exact details shown ordescribed.

1. A covering system for use with an open top container, the systemcomprising: first and second frame members longitudinally spaced fromone another and pivotable about a longitudinally extending axis relativeto one another; an elongated flexible member connected to and extendinglongitudinally between the frame members; and a tarpaulin; wherein theframe members, flexible member and tarpaulin are pivotable between agenerally horizontal covered position adapted to cover the open topcontainer and an uncovered position adapted to allow access to the opentop; and the flexible member is required to transfer sufficient forcefrom the first frame member during pivotal movement thereof to thesecond frame member in order to pivotally move the second frame memberout of the covered position.
 2. The system of claim 1 wherein the entiretarpaulin flips over during movement from the covered position to theuncovered position.
 3. The system of claim 1 wherein the frame members,flexible member and tarpaulin are pivotable approximately 270 degreesabout the axis between the covered position and the uncovered position.4. The system of claim 1 further comprising a first end on each framemember adjacent which it is pivotable about the axis; a second opposedend on each frame member distal the axis; and wherein the flexiblemember is connected to each of the frame members adjacent the respectivesecond end thereof; and in the covered position the tarpaulin extendsfrom adjacent the first end of one of the frame members to adjacent itssecond end.
 5. The system of claim 1 further comprising a first end oneach frame member adjacent which it is pivotable about the axis; asecond opposed end on each frame member distal the axis; and wherein theflexible member is connected to each of the frame members adjacent therespective second end thereof; and in the uncovered position thetarpaulin extends from adjacent the first end of one of the framemembers to adjacent its second end.
 6. The system of claim 1 furthercomprising a first end on each frame member adjacent which it ispivotable about the axis; a second opposed end on each frame memberdistal the axis; and a first connection between the tarpaulin and one ofthe frame members adjacent its first end.
 7. The system of claim 1further comprising a first end on each frame member each frame memberadjacent which it is pivotable about the axis; a second opposed end oneach frame member distal the axis; and a first connection between thetarpaulin and one of the frame members generally midway between itsfirst and second ends.
 8. The system of claim 1 further comprising afirst end on each frame member adjacent which it is pivotable about theaxis; a second opposed end on each frame member distal the axis; and anadditional elongated flexible member extending longitudinally fromadjacent the first end of the first frame member to adjacent the firstend of the second frame member.
 9. The system of claim 8 wherein thetarpaulin is connected to the additional flexible member.
 10. The systemof claim 8 wherein the additional flexible member is connected to theframe members adjacent their respective first ends.
 11. The system ofclaim 1 further comprising a first end on each frame member adjacentwhich it is pivotable about the axis; a second opposed end on each framemember distal the axis; and wherein the first and second frame membersin the uncovered position extend downwardly from adjacent the axis totheir respective second ends.
 12. The system of claim 1 wherein thefirst and second frame members in the uncovered position aresubstantially vertical.
 13. The system of claim 1 in combination withthe open top container; wherein the open top container comprises firstand second longitudinally spaced end walls each having a top and bottom,and first and second axially spaced longitudinally extending sidewallseach having a top and bottom and extending between and connected to thefirst and second end walls whereby the end walls and sidewalls definetherewithin an interior chamber with an entrance opening defined by therespective tops of the four walls; and wherein the longitudinallyextending axis is adjacent the top of the first sidewall.
 14. Thecombination of claim 13 wherein the first and second frame members inthe covered position extend from adjacent the top of the first sidewallto adjacent the top of the second sidewall.
 15. The combination of claim13 wherein the first and second frame members in the uncovered positionare external to the first sidewall opposite the second sidewall.
 16. Thecombination of claim 13 wherein the first and second frame members arepivotally secured to the first sidewall.
 17. The combination of claim 13wherein the first and second frame members during pivotal movementbetween the covered and uncovered positions extend outwardly fromadjacent the first sidewall in a direction away from the secondsidewall.
 18. The combination of claim 13 wherein each of the framemembers comprises a base rigidly secured to the first sidewall.
 19. Thesystem of claim 1 further comprising a first end on each frame memberadjacent which it is pivotable about the axis; a second opposed end oneach frame member distal the axis; and wherein each of the frame memberscomprises a triangular configuration which is longitudinally wideradjacent the axis than adjacent its distal second end.
 20. The system ofclaim 1 further comprising a longitudinally elongated base on each framemember; first and second beams on each frame member; first and secondlongitudinally spaced pivotal connections about the axis respectivelybetween the first and second beams of each frame member and its base;and a rigid third connection between the first and second beams distalthe axis; the first and second beams angling toward one another from thefirst and second pivotal connections toward the rigid third connection.21. The system of claim 1 wherein the axis is a first axis; and thetarpaulin is a first tarpaulin; the covered position is a first coveredposition; the uncovered position is a first uncovered position; andfurther comprising third and fourth frame members longitudinally spacedfrom one another and pivotable about a longitudinally extending secondaxis relative to one another; a second elongated flexible memberconnected to and extending longitudinally between the third and fourthframe members; a second tarpaulin; and wherein the third and fourthframe members, second flexible member and second tarpaulin are pivotablebetween a generally horizontal second covered position adapted to coverthe open top container and a second uncovered position adapted to allowaccess to the open top; and the second flexible member is required totransfer sufficient force from the third frame member during pivotalmovement thereof to the fourth frame member in order to pivotally movethe fourth frame member out of the second covered position.
 22. Acovering system for use with an open top container, the systemcomprising: first and second frame members longitudinally spaced fromone another and pivotable about a longitudinally extending first axisrelative to one another; third and fourth frame members longitudinallyspaced from one another and pivotable about a longitudinally extendingsecond axis relative to one another; a first elongated flexible memberconnected to and extending longitudinally between the first and secondframe members; a second elongated flexible member connected to andextending longitudinally between the third and fourth frame members; afirst tarpaulin; a second tarpaulin; wherein the first and second framemembers, first flexible member and first tarpaulin are pivotable betweena generally horizontal first covered position adapted to cover a firstportion of the open top container and a first uncovered position adaptedto allow access to the first portion of the open top; and the firstflexible member is required to transfer sufficient force from the firstframe member during pivotal movement thereof to the second frame memberin order to pivotally move the second frame member out of the firstcovered position; and wherein the third and fourth frame members, secondflexible member covered position adapted to cover a second portion ofthe open top container and a second uncovered position adapted to allowaccess to the second portion of the open top; and the second flexiblemember is required to transfer sufficient force from the third framemember during pivotal movement thereof to the fourth frame member inorder to pivotally move the fourth frame member out of the secondcovered position.